βIV-Spectrin/STAT3 complex regulates fibroblast phenotype, fibrosis, and cardiac function

Area of Science:

• Cardiovascular Biology
• Cellular Biology
• Fibrosis Research

Background:

• Cardiac fibrosis, a hallmark of cardiovascular disease, results from stress-induced cardiac fibroblast (CF) activation.
• The precise mechanisms governing CF activation in vivo remain incompletely understood.

Purpose of the Study:

• To investigate the role of a βIV-spectrin/STAT3 complex in maintaining the quiescent state of cardiac fibroblasts.
• To determine if this complex is essential for preventing fibrosis and cardiac dysfunction.

Main Methods:

• Utilized genetic and acquired mouse models with βIV-spectrin deficiency.
• Assessed cardiac function, fibrosis, and electrical impulse conduction.
• Examined STAT3 nuclear accumulation, transcriptional activity, and gene expression.
• Investigated the effects of βIV-spectrin fragment expression and STAT3 inhibition.

Main Results:

• βIV-spectrin deficiency led to increased cardiac fibrosis, impaired cardiac function, and conduction defects.
• Loss of βIV-spectrin promoted STAT3 activation and CF activation.
• Restoration of quiescent phenotype was achieved via βIV-spectrin fragment expression or STAT3 inhibition.
• In vivo STAT3 inhibition ameliorated fibrosis and cardiac dysfunction in βIV-spectrin deficient mice.

Conclusions:

• The βIV-spectrin/STAT3 complex is essential for maintaining cardiac fibroblast quiescence.
• Dysregulation of this complex contributes to fibrosis and cardiac dysfunction in cardiovascular disease.
• Targeting the βIV-spectrin/STAT3 pathway represents a potential therapeutic strategy for cardiovascular remodeling.